Artist Eric Fisher had a brilliant idea how to find out where the most popular places in a city are. By using Flickr (the oh-so-popular image sharing site) he was able to countercheck if the image was made by a tourist or by a local. Add geotagging to the picture and Eric was able to make these neat looking maps of well-known cities.

A red spot means a picture was taken at that location by a tourist. A blue spot means a picture was taken at that location by a local.